Just a couple of quick thoughts, etc....

[Ixontes]

First and foremost.....Why not double XP from here on out???

Next......
I have played this game for about 5 years and just within the past 2 weeks leveled up one of my characters on one of my accounts to 50. I know this may sound cheesy but I think it is because I enjoyed the game just to enjoy it, and not for leveling, grinding, hours of endless missions, etc.... I have 2 accounts. One has a level 50, a few level 30s, and a bunch of 10s and 20s, the other (newer one), I have a level 43, and a bunch of >30 toons. I play just to enjoy the game and get away from the anxiety of life. Just wanted to share this.

[Rotten Luck]

That how I was.  Rotten Luck was the first I got to 50 and beyond.  Now that I'm stuck on Free setting those Incarnate abilities are locked out.

[Copper Cockroach]

Yeah, I was wondering about this. I know they can only run one "event" at a time... but why not run the game on Perma-Double XP Mode during the week, and switch to Holiday Events or Invasions on the weekends?

[Kaiser Tarantula]

For what it's worth, Double XP is on permanently on Beta server for the rest of the game's life, according to Arbiter Curry.